Hey there,
I'm an international student and I got my masters at the University of Glasgow from 2006-2007. I lived in Kelvinhaugh Gate and I would recommend it. Its not perfect of course, but a lot of my friends lived in Queen Margaret and although its a nicer complex, its pretty far from the university and the shops. However, Q.M. is closer to Byres Road where there are 3 grocery stores, Boots for toiletries and things, and the main university subway stop is there as well. Its a fun street and occasionally we saw some scottish actors and footballers walking around with their families. There are also lots of cute coffee shops and one nightclub.
As for Kelvinhaugh Gate, its closer to Argyle street which isn't as nice as Byres, but its closer to the university and the Kelvingrove museum and park is lovely to walk through on your way to the university. I did Classics and Archaeology, so Kelvinhaugh Gate was closer to the Classics Dept., which helped me on the days I was running late. I also liked it when Glasgow had its nasty windy/rainy season..the less time walking outside when one's raincoat is slapping you in the face, the better.
The only thing I would be wary of in Kelvinhaugh is the laundry situation....there was only 1 laundry room with 5 washers and 5 dryers for the entire complex...it definitely got annoying. I think Q.M. is better from what I saw. Another issue was how thin the walls were. I think Q.M. was a little better for that as well.
So anyway, there are some pros and cons...hope this helps! I'd still choose Kelvinhaugh if I had to do it all over again. It helps not to worry about bills and such...just pay your accommodation fee and worry about your studies!